40 
Without wishing to lay too much stress upon the fact, I 
may draw attention to the many and singular relations which 
obtain between that wonderful and apparently isolated fish, 
Lepidosiren, sole member of its order, and the cycloid Glyp- 
todipterine, Ctenododipterine, Phaneropleurine and Ccelacanth 
Crossopiterygidcc. Lepidomen is, in fact, the only living fish 
whose pectoral and ventral members have a structure analo- 
gous to that of the acutely lobate paired fins of UolopiychiuSy 
of Dipterus, or of Fhaneropleiiron, though the fin rays and 
surface scales are still less developed in the modern than in 
the ancient fish. The endo-skeleton of Lc2ndosiren, again, is, 
as nearly as possible, in the same condition as that of 
ThanevopleuTon, and is more nearly similar to the skeleton 
of the Coelacanths than that of any other recent fish ; while, 
perhaps, it not stretching the search for analogies too far to 
discover in the stiff- walled lungs of Lepidosiren, a structure 
more nearly representing the ossified air-bladder of the 
Coelacanths than any with which we are at present acquainted, 
among recent or fossil fishes. Furthermore, Lepidosiren is 
the only fish whose teeth are comparable in form and arrange- 
ment to those of Dij^teriis. Though Lepidosimi may not be 
included among the Crossopterygidas, nor even in the order 
of Granoidei, the relations just pointed out are not the less 
distinct ; and, perhaps, they gain in interest when we reflect, 
that while Polypterus, the modern representative of the 
rhombiferous Crossopterygidse, is that fish which has the 
most completely lung-like of all air-bladders, Lepidosiren, 
which has just been shown to be, if not the modern represen- 
tative of the cycliferous Crossopterygidac, yet their * next of 
kin,' is the only fish provided with true lungs. These are 
unquestionable facts. I leave their bearing upon the great 
problems of zoological theory to be developed by every one 
for himself.'' 
In addition to these cautious anticipations, bold speculations 
